iPhone Bluetooth onnects fine, so can't comment on pairing.
I tend to not get too fancy as it asking for trouble. The easiest way in my mind is to just record commonly used voice tags to the car and not the phone voice tags. This works fine, and if you swap phones, it will still work seamlessly (as long as numbers on the phones are the same). Just had the iPhone in for repair and used my old reliable brick. Instant hook up (different bluetooth name) and voice tags work straight away.